edited by Albert C. Baugh
Appleton-Century-Crofts, 1948.
Buku Teks SO
Klarer, Mario, 1962-
Routledge, 2005
Buku Teks SO
Klarer, Mario, 1962-
Routledge, 2005
Buku Teks SO
Ayers, David
Blackwell Publishing, 2008
Buku Teks SO
Whitla, William
Wiley-Blackwell, 2010
Buku Referensi